The present invention relates to a filler pipe for a fuel tank of a motor vehicle which is provided at its cap end with a cylindrical insert whereby an elastic sealing ring is arranged between an outer surface of the insert and an inner surface of the filler pipe made of plastic material.
With a known arrangement of the aforementioned type (EP-A 0 210 322) an insert made of metal is inserted into a preassembled hollow cylindrical extension of the filler pipe made of plastic material, whereby for axially fixing of the insert a flange connection is realized subsequently between the insert and the filler pipe. Furthermore, an elastic sealing ring is clamped-in between an outer surface of the insert and an inner surface of the filler pipe, which is formed by an O-ring.
This arrangement entails the disadvantage that for purposes of the connection of the filler pipe and insert, several time-consuming and cost-intensive operating steps are necessary, as a result of which the manufacturing costs are increased. Additionally, an annular groove has to provided at the insert for the axial fixation of the 0-ring because the O-ring would otherwise displace in the axial direction.
It is the object of the present invention to provide a simple cost-favorable connection between the insert and filler pipe. Therebeyond, a functionally correct sealing between insert and filler pipe is to be assured. The underlying problems are solved according to the present invention in that the sealing ring has a profiled elongated cross-sectional shape and is mounted on the insert under prestress and in that the sealing ring and the insert are fixed by the externally disposed filler pipe. The principal advantages achieved with the present invention reside in that an automatic fastening for the sealing ring in the axial direction is achieved by the profiled elongated sealing ring mounted under prestress on the insert. A simple cost-favorable connection between the insert and the filler pipe is achieved by the common blow-molding of the insert and of the sealing ring. The grooves provided at the inner surface of the sealing ring assure that the sealing ring cannot displace itself along the outer surface of the insert. The cross-sectional enlargements provided at the outer surface of the sealing ring effect a good form-locking connection between the sealing ring and the filler pipe. If fuel should reach the sealing ring, then the sealing ring made of rubber or plastic material will swell, and the seal between the insert and filler pipe is additionally improved. It is achieved by the flat elongated shape of the sealing ring that it is also reliably retained in position during the relatively high pressures which occur during the blow-molding operation. An additional securing of the sealing ring in the axial direction is achieved in that radial beads are locally provided at the insert, on which the sealing ring is mounted.